Composition for the recovery of lithium values from brine and process of making/using said composition

ABSTRACT

The present invention is a composition comprising pellets, each of said pellets consisting essentially of an integral mass of polycrystalline material of randomly disposed crystals of hydrated alumina infused with an amount of LiX to produce LiX/Al(OH) 3  having up to a mol fraction of 0.33 of LiX in the so-produced LiX/Al(OH) 3 , wherein LiX is at least one compound selected from the group consisting of Li hydroxide, Li halide, Li nitrate, Li sulfate, and Li bicarbonate. The present invention further includes methods of preparing the composition and methods of recovery lithium values from brine using the composition.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.08/387,178, filed Feb. 13, 1995, now U.S. Pat. No. 5,599,516, which is acontinuation-in-part of U.S. patent application Ser. No. 08/065,586,filed May 24, 1993, now U.S. Pat. No. 5,389,349.

FIELD OF THE INVENTION

Lithium values are recovered from lithium-containing brines as a lithiumsalt using altered polycrystalline hydrated alumina.

BACKGROUND OF THE INVENTION

Previous methods of extracting lithium values from brines which containlithium are disclosed in the following U.S. Pat. Nos.: 4,116,856;4,116,858; 4,159,311; 4,221,767; 4,291,001; 4,347,327; 4,348,295;4,348,296; 4,348,297; 4,376,100; 4,381,349; 4,430,311; 4,461,714;4,472,362; and 4,477,367. These patents pertain, in various ways, tocreating lithium aluminates within the interstices or pores of ionexchange resins, or on other substrates, porous and non-porous.Microcrystalline lithium aluminates formed within ion exchange resinsare useful in selectively removing lithium values from Li-containingbrines.

Over the years, it has been found that ion exchange resin compositionswere often fouled by substances in the brine, such as hydrocarboncontaminants, that rendered the ion exchange resin incapable ofrejuvenation requiring re-manufacture of resin.

In Lithium—Current Applications in Science, Medicine and Technology, R.O. Bach Editor, published by John Wiley and Sons, 1985, there is anarticle on pp. 29-34, authored by W. C. Bauman, J. L. Burba, III and J.M. Lee, titled “Structure And Operation Of Dow's New Lithium-SelectiveIon-Exchange Resin” containing some background information of relevanceto the subject matter of this present disclosure.

We have now, unexpectedly, found it preferable to infuse LiOH into thepolycrystalline hydrated alumina pellets, herein referred to as Al(OH)₃,by reacting it, in the presence of water, with LiOH in the absence ofNaCl or other salt. We find that infusion of LiOH into Al(OH)₃ pelletsproceeds with maintenance of pellet integrity up to and beyond 0.2 molfraction, and up to 0.33 mol fraction of LiOH in the so-formedLiOH/Al(OH)₃. Furthermore, we find that having initially prepared theintercalation in the absence of NaCl or other salt, the pellets can thenbe converted to the LiCl form with aqueous HCl and used for the specificrecovery of LiCl from brine without pellet breakage. Our prior work withintercalating LiCl directly into the crystals to form LiCl/Al(OH)₃ waslimited to amounts of up to about 0.2 mol fraction of LiCl in order toavoid breaking up the pellets. Also, we have now determined that theseso-altered polycrystalline alumina pellets containing more than 0.2 molfraction, up to 0.33 mol fraction, of LiCl in the LiCl/Al(OH)₃ producedin the presently described method, offer significant improvements incosts and efficiency for recovering LiCl from brine compared to thematerial identified hereinabove as being of relevance in “Structure AndOperation of Dow's New Lithium-Selective Ion-Exchange Resin.”

SUMMARY OF THE INVENTION

This invention comprises an altered polycrystalline hydrated aluminacomposition, its preparation, and its use for selectively recoveringlithium values from brines which contain lithium ions.

The composition comprises pellets, each of said pellets consistingessentially of an integral mass of polycrystalline hydrated aluminapellets morphologically altered by the infusion therein of LiOH (lithiumhydroxide) which creates active lithium-specific sites within thecrystal layers of the alumina, essentially without. decrepitation of thelayered structure. The composition is prepared by adding an aqueous LiOHsolution to a polycrystalline hydrated alumina (especially Gibbsite) inan amount to provide up to 0.33 mol fraction of LiOH in thepolycrystalline LiOH/Al(OH)₃.

The so-prepared infused alumina pellets are used in the process ofremoving lithium values from brine by contacting it with a solution ofLiX (where X is nitrate, sulfate, bicarbonate, halide, or other acidsalt moiety, especially chlorine) to convert the LiOH to LiX. Theresulting LiX/Al(OH)₃, having a mol fraction of LiX of up to 0.33,especially from above about 0.2 and up to 0.33, is a beneficialimprovement in comparison with the previously attained loadings of up toabout 0.2 mol fraction of LiX disclosed in our above-identified relatedapplication.

DETAILED DESCRIPTIONS INCLUDING BEST MODE CONTEMPLATED

In this disclosure the LiX of greatest interest is LiCl, and the brinesof greatest interest, besides seawater, are subterranean brines, such asthat from the Smackover formation which runs largely through Arkansasand into Texas.

In preparing the unique compositions of this invention, there isselected a polycrystalline hydrated alumina of pellet size which issuitable for use in a column without encountering excessive packing andblinding which interferes with efficient flow of liquids through a bedof the pellets. We find it preferable to use polycrystalline pellets ofhydrated alumina known as crystalline Gibbsite, such as that which iscommercially available as LaRoche H-30TM, Reynolds Metal RH-30TM, andAlcoa C-30TM. Other polycrystalline pellets can be used, such as thosemade from Bayerite, Norstrandite or Bauxite.

The process known as the Bayer process is used to manufacturepolycrystalline hydrated alumina from various alumina-containing ores orminerals (usually bauxite) to make a coarse product which is suitablefor use in this invention. Preferably the particle size of the pelletsis not smaller than about 140 mesh, U.S. standard sieve size, and can beas large as about 10 mesh U.S. standard sieve size.

In general, the altered polycrystalline pellets are prepared by addingan aqueous LiOH solution to a polycrystalline hydrated alumina, hereinAl(OH)₃, esp. Gibbsite, in an amount to provide LiOH/Al(OH)₃ containing,preferably, from about 0.2, up to maximum of 0.33 mol fraction of LiOHas an intercalant. This is readily done in a vessel at an ambienttemperature in the range of 0° C. to 25° C. for 24 to 48 hours whileadding enough pure water to keep the pellets submerged.

Preparation of pellets for use in the recovery of LiCl from brineconsists in the neutralization of the LiOH/Al(OH)₃ pellets with diluteHCl in excess H₂O, preferably in the presence of NaHCO₃ as a buffer atpH of about 5 to 6. This neutralization step can be done at ambienttemperature, and does not normally require more than a few minutes ofgood mixing, depending on the size of the mixing vessel. The buffer isto assure that the acidity does not become excessive.

We have determined that the present invention offers improvements incosts and efficiency for recovering lithium values from brines. Thepolycrystalline alumina pellets of the present invention are soinexpensive, compared with ion exchange resins, that it is more costeffective to discard spent alumina or convert it to other uses than torepeatedly rejuvenate it as an infused alumina. Also, the preparation ofthe lithium-capturing pellets of the present invention is relativelysimple and easily managed in-situ in a vessel in which it is to be used,though it can be prepared in one vessel and then transferred to anothervessel for use. A more concentrated and more pure LiX (where X is ahalide ion, usually chloride) product can be obtained from theLi-containing brine, as compared to the known use of ion exchangeresins.

Furthermore the present invention distinguishes over the relatedinvention of our above cross-referenced application by not requiring aninitial loading of LiX into the hydrated alumina compound in whichpellet breakage was found to be encountered at loadings exceeding 0.2mol per mol of Al(OH)₃.

Once the hydrated alumina has been infused with an initial amount ofLiOH and neutralized with an acid to provide active LiX sites of up to0.33 mol fraction, the LiX is washed out with water to remove much ofthe “loadings” of the active sites and the “unloaded” sites areefficiently used to take up more LiX from brine, and used again aplurality of times before becoming exhausted.

GENERALIZED EXAMPLE

Altered polycrystalline hydrated alumina pellets are prepared by aprocess comprising substantially filling the void volume of the layeredpolycrystalline structure, with a predetermined amount of an aqueousLiOH solution so as to have the LiOH infused (“loaded”) into thepolycrystalline hydrated alumina pellets in an amount to formLiOH/Al(OH)₃ containing more than about 0.2 mol fraction of the LiOHintercalant in the LiOH/Al(OH)₃ crystal structure. At 25° C. infusion ofthe LiOH into the crystals layers of the pellets is complete in a periodof 24-48 hours. The infusion progresses into the hydrated aluminapellets with a slight swelling in particle size without fracture.

We have also found that the LiOH/Al(OH)₃ pellets so-formed may besuspended in water at about 25° C. and neutralized with HCl slowly in aperiod of 1-2 hours at 5-7 pH to produce LiCl/Al(OH)₃ without fracture.The alteration results in infused active sites of LiOH within layers ofan appreciable amount of the crystalline layers of the hydrated alumina,but not to an extent that is enough to cause any substantial breakingapart of the polycrystalline structure The LiOH/Al(OH)₃ so-produced isneutralized with an aqueous acid, HCl, to convert the LiOH in thealumina crystals to LiCl to obtain a mol fraction of LiCl in thecrystals of up to 0.33, preferably a mol fraction in the range of about0.2 to 0.33. After water-washing to remove most of the infused LiCl fromthe alumina crystals, the “vacant” LiCl sites so-produced will acceptadditional LiCl from a lithium-containing brine. This “new” amount ofLiCl can then be reduced in amount (unloaded) by water-washing, leavingenough of the sites to prevent collapse of the altered crystals. The“unloaded” sites are available for extracting more LiCl fromLiCl-containing brines and the loading and unloading of LiCl can be donea plurality of times before the efficiency of the polycrystallinealumina becomes significantly reduced.

Example of Preparation of LiCl/Al(OH)₃ Pellets

156 grams of +140 mesh LaRoche H-30™ Hydrated Alumina is dry mixed with25.2 grams LiOH.H₂O. The mixture is placed in a small stainless steelpot and 125 grams of distilled H₂O is added. The pot is covered and heldat room temperature, 21° C. for 48 hours. 125 grams of distilled H₂O isadded. With gentle stirring of the batch, about 110 grams of 20% HCl isslowly added over a period of about 2 hours, maintaining the pH above3.5. The fluid supernatant contains less that 1% LiCl and has pH of 5-6.The settled volume of solids is 150 ml. The LiCl/Al(OH)₃ pellet bed hasa mol fraction of LiCl of 0.23 and contains 4.0 mols LiCl per liter ofsettled (operating) bed.

Example of LiCl Recovery from Brine With LiCl/Al(OH)₃ Pellets

150 ml of LiCl/Al(OH)₃ pellets made as in above example are used inremoving lithium values from a synthetic 26% NaCl brine which contains2100 mg/liter lithium chloride. Operation is with 2 NaCl resaturationstreams.

The bed is prepared by placing the LiCl/Al(OH)₃ pellets in a jacketedglass column 1-inch in diameter and 2 feet high with a water jacketheated to 80° C. Run water upflow at a rate to give 50% bed expansionfor 30 minutes. Follow the steps below.

1.) run 1900 ml brine upflow at rate to give 50% bed expansion.

2.) allow bed to settle and drain supernatant brine to bed top.

3.) run downflow 52.5 ml 26% NaCl to displace the inter-pellet brine.The effluent is saved for recycle to step 1.) in the next cycle.

4.) run downflow 172.5 ml of of 0.76 mol/liter LiCl saturated with NaCl.The effluent is evaporated and crystallized to provide NaCl forresaturation of the two reflux streams.

5.) run downflow 90 ml of 2.0 mol/liter LiCl saturated with NaCl.

The effluent is saved for recycle to 4.) in next cycle.

6.) run downflow 52.5 ml of 0.76 mol/liter LiCl. The effluent isrecycled to 5.) in next cycle.

7.) run downflow 76.5 ml of 0.76 mol/liter LiCl. 39 ml of effluent issaved as product, and 37.5 ml is resaturated with NaCl and is fed to 5.)in next cycle.

8.) run down flow 211.5 ml of water. 129 ml of effluent is fed to 6.)and 7.) in next cycle and 82.5 ml of effluent is resaturated with NaCland is fed to 4.) in next cycle.

9.) run downflow 52.5 ml brine. Effluent is returned to water storage.

10.) run 1900 ml brine upflow at rate to give 50% bed expansion. Thisstep 10.), the same as 1.) starts the next cycle.

Each cycle produces 0.52 mol LiCl per liter of pellet bed at aconcentration of 2.0 mol/liter with the use of 1.06 liters of water.

The so-formed polycrystalline pellets are used in selectively removinglithium from lithium-containing brine in a process comprising repeatedloading and unloading of the active sites, using water or water whichcontains some LiX for the unloading steps, and LiX-containingconcentrated brine for the loading steps. The unloaded LiX is saved.

While the descriptions disclosed herein are directed primarily torecovering LiCl from NaCl brine, which is preferred and most plentiful,other metal salt brines which contain LiCl, such as. CaCl₂, MgCl₂, andKCl, can demonstrate operability in accordance with this invention. TheLiCl/Al(OH)₃ pellets, when immersed in a chloride brine, absorb anddesorb only LiCl and H₂O; NaCl, MgCl₂, CaCl₂, KCl, SrCl₂, and traceamounts of boric and silicic acids and organic matter frequently foundin natural brines are excluded from the interior structure of thepolycrystalline pellets. Thus a bed of LiCl/Al(OH)₃ pellets operating inthe recovery of LiCl from brine contains only two phases: the hydratedpolycrystalline LiCl/Al(OH)₃ phase and the inter-pellet solution phase.There is no intra-pellet solution phase containing NaCl, CaCl₂, etc. asexists in ion exchange resins. Hence the rinse of excess brine from abed of LiCl/Al(OH)₃ pellets involves a simple displacement of theinter-pellet brine solution by water. Such a displacement may beachieved rapidly at any practical operating temperature with virtuallyno brine dilution and with elimination of all soluble brine components(other than LiCl) from the LiCl/Al(OH)₃ pellets. Comparably, the reversestep of displacing the excess water regenerant by a new cycle of brineis rapid and complete at any temperature without dilution of the brine.The displacement requires a flow of fluid of about 38% of a bed volume.Operation of 0.23 mol fraction LiCl/Al(OH)₃ pellets with a LiCl contentof 4.0 mol/liter of bed in the recovery of LiCl from a saturated NaClbrine containing 2100 mg of LiCl per liter using NaCl resaturation andreflux produces 2.0 molar LiCl at a rate of 0.54 mol LiCl per liter ofbed per cycle using 1 liter of H₂O for each 13 liters of brine and 7lbs. NaCl per 1 lb. LiCl produced

The LiCl/Al(OH)₃ pellets produce more concentrated LiCl at a higherproduction rate with the use of less water than the lithium-selectiveion exchange resin identified hereinabove. The polycrystalline aluminapellets of the present invention are so inexpensive, compared with ionexchange resins, that it is more cost effective to discard spent aluminaor convert it to other uses than to repeatedly rejuvenate it as aninfused alumina. Also, the preparation of the LiCl/Al(OH)₃ pellets ofthe present invention is relatively simple and easily managed in situ ina vessel in which it is to be used, though it can be prepared in onevessel and then transferred to another vessel for use.

One preferred manner of mixing the LiOH with the alumina is to “dry-mix”Li(OH):H₂O and polycrystalline hydrated alumina pellets (e.g. LaRocheH-30 Hydrated Alumina) in the desired mol fraction ratio and add waterto cover the solids and allowing this suspension to stand for 24 to 48hours at about room temperature. This room temperature permits a more“gentle” infusion of the LiOH into the crystal layers to achieve ahigher loading without causing decrepitation of the crystal layerstructure. The suspension of LiOH/Al(OH)₃ pellets is neutralized withdil. HCl acid to 5-6 pH to form the desired LiCl/Al(OH)₃ pellets andthen dried, if desired, before being used in recovering lithium valuesfrom lithium-containing brine. Thusly, pellets are made with a molfraction of LiCl in LiCl/Al(OH)₃ greater than that in the priorinvention which was limited to having not more than 0.2 mol fraction ofLiCl per mol of LiCl/Al(OH)₃ to avoid deleterious lattice expansion ofthe crystal structure which can cause pellet breakage.

There are a number of brines in various places in the world which arerelatively high in the concentration of LiX, especially where Xrepresents a halogen, especially chloride. When the brine is evaporatedseawater, then there is a high concentration of NaCl, with all othermetal halide values being of lower concentration. Other brines often arefound to have more LiX and other metal salts than found in evaporatedseawater. An artificial brine can also be prepared by leaching, eitherroasted or unroasted spodumene, a lithium-containing mineral, with asalt solution.

Particular embodiments other than the above may be employed by others,upon learning of this invention, without departing from the inventiveconcept expressed in this disclosure. Our invention is limited only bythe concept embodied in the claims which follow.

We claim:
 1. A composition comprising pellets, each of said pellets consisting essentially of an integral mass of polycrystalline material of randomly disposed crystals of hydrated alumina infused with an amount of LiX to produce LiX/Al(OH)₃ having up to a mol fraction of 0.33 of LiX in the so-produced LiX/Al(OH)₃, wherein LiX is at least one compound selected from the group consisting of Li hydroxide, Li halide, Li nitrate, Li sulfate, and Li bicarbonate.
 2. The composition of claim 1, wherein LiX is LiCl.
 3. The composition of claim 1, wherein LiX is LiOH.
 4. The composition of claim 1, wherein the polycrystalline material is at least one selected from the group consisting of Gibbsite, Bauxite, Nordstrandite, and Bayerite.
 5. The composition of claim 1, wherein the polycrystalline material is Gibbsite.
 6. The composition of claim 1, wherein the polycrystalline material is Gibbsite and LiX is selected from the group consisting of LiOH and LiCl.
 7. The composition of claim 1, wherein the pellets are of a particle mesh size within the range of greater than 140 to less than 10 United States Standard Sieve Size.
 8. The method of preparing the composition of claim 1, said composition comprising an integral mass of randomly disposed polycrystalline hydrated alumina pellets having LiX infused in at least an appreciable amount of the crystal layers, said method comprising: contacting the pellets with an aqueous LiOH solution to form partially expanded hydrated alumina, LiOH/Al(OH)₃, having up to a 0.33 mol fraction of LiOH in the LiOH/Al(OH)₃, contacting the pellets with HX to convert the LiOH to LiX, wherein X represents a moiety selected from the group consisting of halide, nitrate, sulfate, and bicarbonate.
 9. The method of claim 8, wherein the HX is HCl.
 10. The method of claim 8, wherein the hydrated alumina is selected from the group consisting of Gibbsite, Bauxite, Nordstrandite, and Bayerite.
 11. The method of claim 8, wherein the hydrated alumina is Gibbsite.
 12. The method of claim 8, wherein the particle mesh size of the pellets is within the range of greater than 140 to less than 10 United States Standard Seieve Size.
 13. The method of claim 8, wherein the temperature at which the infusion is carried out is in the range of not less than about 0° C. to 25° C.
 14. A process for recovering Li values from brine which contains LiX, where X is selected from the group consisting of halide, nitrate, sulfate and bicarbonate, said process comprising: (a) position in a recovery vessel a bed volume of pellets of the composition of claim 1, said pellets comprising polycrystalline hydrated aluminum containing infuse LiX in an amount of up to 0.33 mol fraction of LiX in the LiX/Al(OH)₃; (b) passing LiX-containing brine through the bed of pellets until the pellets are loaded with LiX from the brine; (c) displacing brine held-up in the bed by using concentrated NaX; (d) unloading LiX from the pellets by flowing through the bed an aqueous solution of LiX which is not saturated; (e) displacing the LiX from the bed using concentrated NaX and repeating the sequence of steps (b) through (e) a plurality of times.
 15. The process of claim 14, wherein LiX is LiCl and NaX is NaCl.
 16. The process of claim 14, wherein the concentrated NaX is saturated NaX, which is kept saturated by additional NaX.
 17. The process of claim 14, the mol fraction of LiX is in the range between 0.2 and 0.33.
 18. The process of claim 14, wherein the LiX-containing brine is naturally-occurring Smackover brine.
 19. The process of claim 14, wherein the LiX-containing brine is synthetic brine derived by brine leaching of spodumene.
 20. The process of claim 14, wherein the polycrystalline hydrated alumina is at least one obtained from the group of hydrated alumina-containing materials consisting of Gibbsite, Bauxite, Bayerite, and Nordotrandite. 